# What is the difference between TE and TI?

I have done some research about the subject but I can't find the difference between Temperature Element (TE) and Temperature Indicator (TI)

Here is an image of the P&ID of the project am working on if it can help clarify my question.

• ...and what have you found in your research? Jan 29, 2018 at 15:59
• that is they are both instrument of temperature measurement, but i dont know what is the key difference Jan 29, 2018 at 16:01

The element does the measuring and the indicator shows the value.

If you think of a simple thermometer, the bulb at the bottom measures the temperature and the glass tube indicates the value...

• well in the exampl that i have, there is a TE with TW ( thermowell ) and the TI is also accompanied with a TW even thou he only indicate the value ? Jan 29, 2018 at 16:12
• @AzedS The TI (or the reference/cold junction) needs to be at a known temperature in order to solve the simple linear equations that Seebeck effects demand. An easy way to keep something at a known temperature is to place it in a bath of liquid/use a triple point of water cell or a thermowell. You can also use cold junction compensation, though and even some NMI labs use this. Jan 30, 2018 at 1:34

Temperature indicator consists of two parts: the first part is the temperature element itself and the second part is the electronic part that conditions the signal and convert it to 4 to 20 and then send it to control system .

TI = Temperature Indicator; Shows temperature local (in pipe, canal, wall, …) TT = Temperature Transmitter; Remote monitoring temp. (0-10V, 4-20mA, ...) TE = Temperature Element; Remote monitoring temp. by resitance (Pt100, NTC 5k, ...)

TTI = Temperature Transmitter Indicator; Remote monitoring temp. with display

PT = Pressure Transmitter TA = Temperature Alarm TAh = Tempreature high Alarm FI = Flow Indicator QTrh = Quality Transmitter relative humidity